Three-way transition fitting for combustion air piping

ABSTRACT

A transition fitting interconnects a furnace combustion air chamber to an air duct supplying combustion air to the furnace. The fitting includes a housing portion having opposed first opening and second openings, the first opening being disposed adjacent a furnace combustion air chamber upon installation and three tubular portions connected to the housing portion and disposed adjacent to the second opening. Each of the three tubular portions define a central axis and have a first opening into the housing portion and a second opening configured to receive an inlet air duct. One tubular portion is disposed at an angle to the central axes of the other two tubular portions. A peripheral flange portion sealably attaches the housing portion to a frame portion of a furnace. A removably attachable cap is configured to selectively close a tubular portion not connected to an external air duct.

FIELD OF THE INVENTION

The present invention is directed to a three-way fitting for interconnecting the burner chamber of a furnace to an inlet air supply duct.

BACKGROUND OF THE INVENTION

Typically, gas furnaces for use in residential dwellings are designed to be installed in more than one configuration. The furnace unit may be installed for vertical airflow i.e., up or down, or for horizontal airflow, i.e., left or right, through the furnace. The units may be free-standing vertically or placed horizontally on their side. All furnaces require a source of supply or inlet air for fuel combustion. Gas furnaces include a chamber which houses the gas burners, in which inlet air mixes with the natural gas and is ignited to produce a source of heat. In a new furnace before installation, the burner chamber is equipped with an opening for interconnection to an air inlet duct in a building. Generally, this opening is equipped with only a flange about the periphery for connecting the duct to the burner chamber of the furnace. However, in many instances, it is the case that the air inlet duct is not disposed adjacent to or in line with the burner chamber. When that occurs, the furnace installer must adapt the air inlet duct to the burner chamber flange by use of various elbows and customized duct fittings. Often it is required of the furnace installer to fabricate the duct fittings in the field out of sheet metal parts or tubular pieces. Custom fittings and fabrication of duct fittings in the field require additional installation time, and special material and tools, all of which adds cost and inconvenience to the furnace installation.

Therefore, there is a need for a furnace inlet air transition to a burner chamber that provides an easy connection to the outside air duct regardless of the location of the outside air duct.

SUMMARY OF THE INVENTION

The present invention is directed to a transition fitting for interconnecting a furnace combustion air chamber to an air duct supplying combustion air to the furnace. The fitting includes a housing portion having a first opening and a second opening opposite the first opening, the first opening being disposed adjacent a furnace combustion air chamber upon installation. At least three tubular portions is connected to the housing portion and disposed adjacent to the second opening. Each of the at least three tubular portions defines a central axis and has a first opening adjacent the second opening of the housing portion and a second opening configured to receive an inlet air duct, wherein the central axis of at least one tubular portion is disposed at an angle to the central axes of the other tubular portions. A peripheral flange portion is connected to the housing portion and disposed adjacent the first opening of the housing portion, the peripheral flange portion having attachment means for sealably attaching the housing portion to a frame portion of a furnace. At least one removably attachable cap is provided, the at least one removably attachable cap being configured to selectively close a tubular portion not connected to an inlet air duct.

The present invention is further directed to a gas furnace including a housing including a furnace combustion air chamber configured to combust a mixture of a combustible gas from a combustible gas source and air from an air duct supplying combustion air to the furnace. A transition fitting interconnects the furnace combustion air chamber to the air duct. The transition fitting includes a body having a first opening and a second opening opposite the first opening, the first opening being disposed adjacent a furnace combustion air chamber. At least three tubular portions are connected to the body and disposed adjacent to the second opening. Each of the at least three tubular portions define a central axis and have a first opening adjacent the second opening of the body and a second opening configured to receive the air duct, wherein the central axis of at least one tubular portion is disposed at an angle to the central axes of the other tubular portions. A peripheral flange portion is connected to the body and disposed adjacent the first opening of the body, the peripheral flange portion being configured to sealably attach the body to the housing. At least two removably attachable caps are provided, the at least two removably attachable caps being configured to selectively close the tubular portions of the at least three tubular portions not connected to the inlet air duct.

One advantage of the present invention is that it provides the installer with flexibility in connecting the air inlet pipe from the top or bottom of the furnace, or to the side of the furnace, without having to modify any internal parts of the furnace.

Another advantage of the present invention is that it reduces or eliminates the need for excessive field fabrication, elbow fittings, and custom fittings in the installation of a gas furnace.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are opposed perspective views of a three-way transition fitting of the present invention.

FIG. 3 is a front view of the transition fitting of the present invention.

FIG. 4 is a side view of the transition fitting of the present invention.

FIG. 5 is a cross-section of the transition fitting taken along line 5-5 in FIG. 3 of the present invention.

FIG. 6 is a cross-section of the transition fitting taken along line 6-6 in FIG. 3 of the present invention.

FIG. 7 is a cross-section of the transition fitting taken along line 7-7 in FIG. 4 of the present invention.

FIG. 8 is a perspective view of a cap of the present invention.

FIG. 9 is a side view of the cap of the present invention.

FIG. 10 is a perspective view of an alternate embodiment of a three-way transition fitting of the present invention.

FIG. 11 is a perspective view of an alternate embodiment of a three-way transition fitting of the present invention.

FIGS. 12-14 are perspective views showing different furnace installations with the three-way transition fitting of the present invention.

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a three-way inlet air fitting is generally designated as 10. The fitting 10 includes a housing portion or transition portion 12 defined by a first pair of opposing side portions 14 a, 14 b and a second pair of opposing side portions 16 a, 16 b. One end of each side portion 14 a, 14 b is connected to flange portions 18 b, 18 c. One of the side portions 16 b has a lip 32 extending therefrom at one edge. The remaining side portion 16 a is connected to a flange portion 18 a extending perpendicularly therefrom. Flange portions 18 a, 18 b, 18 c include apertures 34 formed therein to correspond with apertures in the structure of the furnace, for attaching the transition portion 12 to the furnace. Other suitable techniques for attachment may be substituted for the flanges as are commonly known to those skilled in the art.

First and second tubular portions 22, 42 cross an axis 36 of the fitting 10 at the end of the side portions 16 a, 16 b opposite of the flange portions 18 a, 18 b, 18 c adjoining the furnace. A third tubular portion 28 having center axis 36 preferably intersects the first and second tubular portions 22, 42 in axial alignment with the fitting 10. That is, axis 36 extends through axes 50, 52. The intersecting tubular portions 22, 42, 28, define three respective openings 24, 26 and 30. Openings 24 and 26 are preferably axially disposed at 180 degrees with respect to each other as measured between their respective axes 50, 52, and at 90 degrees axially with respect to opening 30 in third tubular portion 28 as measured from respective axis 36. In the embodiment shown in FIG. 1, this arrangement substantially defines a T-configuration in fluid communication with the hollow interior of the transition portion 12. Also, in the embodiment shown in FIG. 1, the tubular portions 22, 42 and the respective openings 24, 26 do not share the same axis (50, 52), but the two axes 50, 52 are offset and parallel to each other. In yet another embodiment of the invention, the two axes 50, 52 may coincide. Thus, as discussed in additional detail below, a burner chamber of a furnace to which the transition portion 12 attaches may be easily directly interconnected with an inlet air duct extending either horizontally or vertically therefrom, without requiring specially designed fittings or other adapter to be field installed.

Referring to FIGS. 1-7, the transition portion 12 opens into the burner chamber of the furnace through an opening 40. The side portion 16 a preferably tapers generally symmetrically from flanges 18 b, 18 c to form a connection with first tubular portion 22. An opening 44 allows inlet air to flow between tubular openings 24, 26 and 30, and opening 40 into the furnace. As described below, two of three tubular openings 24, 26 and 30 are closed once the remaining tubular opening is connected to an air duct to provide a source of combustion air. Preferably, a cap 54, as shown in FIGS. 8 and 9, is used to close two of the three openings 24, 26 and 30. Side portions 14 a, 14 b terminate at the edges of tapered side portions 16 a, 16 b to enclose the air passage within the transition portion 12.

Also shown in FIGS. 8-9 are caps 54 that are removably attached to any two of the three tubular portions 22, 28 and 44 to seal all but one of the respective openings 24, 26, 30. In practice, only one of the openings 24, 26, 30 is connected to an air inlet duct (not shown), although more than one opening could be connected to multiple inlet ducts if desired. The installer determines which opening of the three openings 24, 26, 30 is selected according to the most convenient routing to an outside air source of the building via inlet duct 108. If the selected opening has a cap 54 affixed to it, the cap 54 is simply removed to provide the uncapped opening. The selected opening is then capable of interconnection with the air inlet duct. Thus the fitting of the present invention provides the installer the option of three directional openings for connection to a single inlet air duct.

Cap 54 includes a tapered surface 58 defining a portion of a circular cone for insertion into the tubular openings 24, 26, 30 to provide a fluid tight, frictional joint. The cap 54 includes a rib 56 to provide an installer with sufficient leverage to removably install the caps 54 as required.

Referring back to FIGS. 1-7, tubular portions 22 and 42 are preferably disposed on opposite sides of fitting 10. First tubular portion 22 penetrates side portion 16 a and second tubular portion 42 penetrates side portion 16 b. Third tubular portion 28 is arranged substantially perpendicular to both first tubular portion 22 and second tubular portion 42, although first and second tubular portions 22, 42 are not necessarily aligned coaxially. In the embodiments that are illustrated in FIGS. 1-7, first and second tubular portions 22, 42 have respective parallel center axes 50, 52 that are slightly offset, although the tubular portions may also share the same axis in an alternate embodiment (not shown). As shown in FIG. 2, the tubular portions 22, 42 and 28 are configured in an inverted T, allowing the furnace installer the options of a direct connection to the inlet air duct in the vertical direction, and in both directions horizontally. Alternately, depending upon the furnace interface with the fitting, the inverted T can allow the furnace installer the options of a direct connection to the inlet air duct in the horizontal direction and in both directions vertically. It should be noted that the orientation of the fitting 10 is fixed with respect to the position of the furnace, which may be placed in various orientations, e.g., for upward air flow, downward air flow or for horizontal air flow. Irrespective the orientation, tubular portions 22, 42, and 28 each have incorporated therein means to prevent an inlet duct from being inserted overly far within the fitting 10. For example, if an inlet duct were inserted too far inside first tubular portion 22 so as to extend past the transition portion 12, the fitting could not operate properly, since the opening to the transition portion 12 would be closed by the inlet duct, preventing sufficient air from flowing to the burner chamber. To achieve insertion depth control in the first tubular portion 22, referring to FIG. 5, side portion 16 a extends to form an annular stop 46, resembling a “C” in FIG. 5. Similarly, referring to FIG. 6, a pair of opposed stops 48 extend inwardly from respective side portions 14 a, 14 b within opening 26. Moreover, referring to FIGS. 2 and 3, it is shown that side portion 16 a will act as a stop to prevent over-insertion of an inlet duct in third tube portion 28.

FIGS. 12-14 are directed to a furnace 100 that includes a burner chamber 110, which is secured to the transition portion 12 of the fitting 10, which fitting 10 also being connected to an inlet duct 108 for providing outside air to the burner chamber 110. In FIG. 12, the inlet duct 108 extends vertically downward, and via a single elbow fitting 112, can be configured so that only an additional straight segment of the inlet duct 108 is required to connect with the fitting 10. As shown in FIG. 12, the inlet duct 108 is directed through an aperture 104 formed in a furnace panel 102 a opposite the end of the furnace 100 containing the burner chamber 110. Optionally, a removable cap 106 can be used to close an aperture 104 in each of panels 102 b, 114 that are adjacent to the fitting 10. Otherwise, the cap 106 can be in the form of a knock-out, such as commonly used in the art.

As shown in FIG. 13, similar to FIG. 12, the inlet duct 108 extends vertically downward, and via a single elbow fitting 112, can be configured so that the end of the elbow fitting 112 opposite the end connected to the vertically disposed portion of the inlet duct 108 directly connects with the fitting 10. However, in FIG. 13, the elbow fitting of inlet duct 108 is directed through an aperture 104 formed in a furnace panel 102 b adjacent the end of the furnace 100 containing the burner chamber 110. Optionally, a removable cap 106 can be used to close the aperture 104 in each of panels 102 a and 114. Otherwise, the cap 106 can be in the form of a knock-out, such as commonly used in the art.

Finally, as shown in FIG. 14, the inlet duct 108 extends vertically upward and can be configured to directly connect with the fitting 10. However, in FIG. 14, the inlet duct 108 is directed through an aperture 104 formed in a furnace panel 114 adjacent the end of the furnace 100 containing the burner chamber 110. Optionally, a removable cap 106 can be used to close the apertures 104 in each of panels 102 a and 102 b. Otherwise, the cap 106 can be in the form of a knock-out, such as commonly used in the art.

It is to be understood that openings 24, 26 are not required to be disposed at 180 degrees to each other, as these openings could be disposed at angles that are significantly less than 180 degrees. For example, referring to FIG. 10, first tubular portion 22 extends so that opening 24 is associated with axis 150 and second tubular portion 42 extends so that opening 26 is associated with axis 152, which angle between axis 150 and axis 152 being significantly less than 180 degrees, and conceivably parallel to each other. Similarly, it is also to be understood that opening 30 is not required to be disposed 90 degrees axially from openings 24, 26. In other words, third tube portion 28, as measured from axis 136, can define an angle measuring anywhere between zero and 180 degrees from each of axis 150 of opening 24 and axis 152 of opening 26. However, since most air inlet ducts extend substantially parallel to the ceiling, walls and floor which are mutually perpendicular to each other, the embodiment as shown in FIG. 1 is preferred.

FIG. 11, which is otherwise similar to FIG. 10, includes joints 60 for each of the tubular portions 22, 28, 42 to permit an amount of angular adjustability of each of the tubular portions 22, 28, 42. For example, first tubular portion 22 extends to an additional first tubular portion 122, first tubular portion 22 and first tubular portion 122 being separated by joint 60, which permits a relative sliding rotational motion about axis 50 between the first tubular portion 122 and the first tubular portion 22. That is, by applying a rotation 62 of the first tubular portion 122 about axis 50 by virtue of joint 60, axis 150 traces a periphery of a circular cone 64, providing angular adjustment of the position or orientation of axis 150 between axis 150 and an axis 150′.

Similarly, second tubular portion 42 extends to an additional second tubular portion 142, second tubular portion 42 and second tubular portion 142 being separated by joint 60, which permits a relative sliding rotational motion about axis 52 between the second tubular portion 142 and the second tubular portion 42. That is, by applying a rotation 62 of the second tubular portion 142 about axis 52 by virtue of joint 60, axis 152 traces a periphery of a circular cone 64, providing angular adjustment of the position or orientation of axis 152 between axis 152 and axis 152′.

Additionally, third tubular portion 28 extends to an additional third tubular portion 128, third tubular portion 28 and third tubular portion 128 being separated by joint 60, which permits a relative sliding rotational motion about axis 36 between the third tubular portion 128 and the third tubular portion 28. That is, by applying a rotation 62 of the third tubular portion 128 about axis 36 by virtue of joint 60, axis 136 traces a periphery of a circular cone 64, providing angular adjustment of the position or orientation of axis 136 between axis 136 and axis 136′.

In addition to angular adjustment of tubular portions 122, 142 and 128 about respective axes 50, 52 and 36, the first tubular portion 22 can be configured so that the first tubular portion 22 is rotatable about axis 50 with respect to transition portion 12. The effect of imparting a rotation 64 of first tubular portion 22 about axis 50 similarly imparts a rotation about axis 50 of the third tubular portion 28 and the third tubular portion 128. That is, by applying a rotation 64 of the third tubular portion 28 and the third tubular portion 128 about axis 50, the orientation of axis 36 of the third tubular portion 28 becomes axis 36′, and the adjustable orientation of axis 136 between axis 136 and 136′ of the third tubular portion 128 as previously discussed above becomes between axis 136 a and 136 a′.

In summary, while fitting 10 can include a fixed, unitary construction as shown in FIG. 1, other embodiments of the fitting can include any combination of adjustments of the angular position or orientation of axes of the tubular portions.

The embodiments shown in the figures are examples of several configurations and are not intended to limit the scope of the invention.

One skilled in the art can appreciate that the fitting of the present invention can be constructed of metal or a polymer or other suitable material having sufficient structural strength and compatibility with a heating system.

It is also to be understood that the fitting of the present invention can include more than three tubular portions. The axes of the tubular portions can be disposed at angles other than 90 or 180 degrees, and the angular position or orientation of any one combination of the tubular portions can also be adjustable. The fitting can also be of unitary construction. In addition, more than one of the tubular portions can be connected to an inlet duct, the tubular portions connected to inlet duct(s) not requiring caps.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

1. A transition fitting for interconnecting a furnace combustion air chamber to an air duct supplying combustion air to the furnace, the fitting comprising: a housing portion having a first opening and a second opening opposite the first opening, the first opening being disposed adjacent a furnace combustion air chamber upon installation; at least three tubular portions connected to the housing portion and disposed adjacent to the second opening; each of the at least three tubular portions defining a central axis and having a first opening adjacent the second opening of the housing portion and a second opening configured to receive an inlet air duct, wherein the central axis of at least one tubular portion is disposed at an angle to the central axes of the other tubular portions; a peripheral flange portion connected to the housing portion and disposed adjacent the first opening of the housing portion, the peripheral flange portion having attachment means for sealably attaching the housing portion to a frame portion of a furnace; and at least one removably attachable cap, the at least one removably attachable cap being configured to selectively close a tubular portion not connected to an inlet air duct.
 2. The transition fitting as set forth in claim 1, wherein at least one pair of the at least three tubular portions have coincident central axes.
 3. The transition fitting as set forth in claim 1, wherein the central axes of at least one pair of the at least three tubular portions are substantially parallel and noncoincident.
 4. The transition fitting as set forth in claim 1, wherein the at least one tubular portion disposed at an angle is substantially perpendicular to at least one of the other tubular portions.
 5. The transition fitting as set forth in claim 1, wherein the at least three tubular portions comprise three tubular portions, the three tubular portions are arranged in a T-configuration, wherein two of the three tubular portions have opposed second openings.
 6. The transition fitting as set forth in claim 5, wherein the third tubular portion of the three tubular portions is substantially aligned with the second opening of the housing portion.
 7. The transition fitting as set forth in claim 5, wherein two of the three tubular portions are disposed vertically.
 8. The transition fitting as set forth in claim 1, wherein the housing portion, the at least three tubular portions and the peripheral flange are of unitary construction.
 9. The transition fitting as set forth in claim 1, wherein an angular position of a central axis of at least one tubular portion of the at least three tubular portions is selectably adjustable with respect to the other tubular portions.
 10. The transition fitting as set forth in claim 1, wherein the at least one removably attachable cap has a tapered surface configured to contact an inner surface of a tubular portion.
 11. The transition fitting as set forth in claim 10, wherein the at least one removably attachable cap has a rib for selective removal from a tubular portion.
 12. The transition fitting as set forth in claim 1, wherein each of the tubular portions has means for preventing over-insertion of an external air duct within the tubular portion.
 13. A gas furnace comprising: a housing including a furnace combustion air chamber configured to combust a mixture of a combustible gas from a combustible gas source and air from an air duct supplying combustion air to the furnace; a transition fitting for interconnecting the furnace combustion air chamber to the air duct, the transition fitting comprising: a body having a first opening and a second opening opposite the first opening, the first opening being disposed adjacent a furnace combustion air chamber; at least three tubular portions connected to the body and disposed adjacent to the second opening; each of the at least three tubular portions defining a central axis and having a first opening adjacent the second opening of the body and a second opening configured to receive the air duct, wherein the central axis of at least one tubular portion is disposed at an angle to the central axes of the other tubular portions; a peripheral flange portion connected to the body and disposed adjacent the first opening of the body, the peripheral flange portion being configured to sealably attach the body to the housing; and at least two removably attachable caps, the at least two removably attachable caps being configured to selectively close the tubular portions of the at least three tubular portions not connected to the inlet air duct.
 14. The gas furnace as set forth in claim 13, wherein at least one pair of the at least three tubular portions have coincident central axes.
 15. The gas furnace as set forth in claim 13, wherein the central axes of at least one pair of the at least three tubular portions are substantially parallel and noncoincident.
 16. The gas furnace as set forth in claim 13, wherein the at least one tubular portion disposed at an angle is substantially perpendicular to at least one of the other tubular portions.
 17. The gas furnace as set forth in claim 13, wherein the at least three tubular portions comprise three tubular portions, the three tubular portions are arranged in a T-configuration, wherein two of the three tubular portions have opposed second openings.
 18. The gas furnace as set forth in claim 17, wherein the third tubular portion of the three tubular portions is substantially aligned with the second opening of the housing portion.
 19. The gas furnace as set forth in claim 17, wherein the two of the three tubular portions are disposed vertically.
 20. The gas furnace as set forth in claim 13, wherein the housing portion, the at least three tubular portions and the peripheral flange are of unitary construction.
 21. The gas furnace as set forth in claim 13, wherein an angular position of a central axis of at least one tubular portion of the at least three tubular portions is selectably adjustable with respect to the other tubular portions.
 22. The gas furnace as set forth in claim 13, wherein the at least two removably attachable caps each have a tapered surface configured to contact an inner surface of a tubular portion.
 23. The gas furnace as set forth in claim 22, wherein the at least two removably attachable caps each have a rib for selective removal from a tubular portion.
 24. The gas furnace as set forth in claim 13, wherein each of the tubular portions has means for preventing over-insertion of the air duct within the tubular portion.
 25. The gas furnace as set forth in claim 13, comprises at least one aperture formed in the housing, wherein a selectably removable cap is disposed in each of the at least one aperture.
 26. The gas furnace as set forth in claim 25, wherein upon removal of the selectably removable cap from the at least one housing aperture, the inlet air duct is receivable inside the housing through the at least one housing aperture. 